South Shields New Central Library and Digital Media Centre ...planning.southtyneside.info/MVM.DMS/Planning... · The likelihood of encountering unexploded ordnance on both development

June 2014

South Shields New Central Library and Digital Media CentrePhase 2 Ground Investigation Report

South Shields New Central

Library & Digital Media Centre

Phase 2 Ground Investigation

Curtins Ref: EB1285

Revision: A

Issue Date: 25 April 2014 (First Issue)

Client Name: Muse Developments

Client Address: Fountain House, 4 South Parade, Leeds, LS1 5QX

Site Address: Ferry Street, South Shields

STRUCTURES • CIVILS • ENVIRONMENTAL • INFRASTRUCTURE • TRANSPORT PLANNING • SUSTAINABILITY • EXPERT ADVISORY SERVICES Birmingham • Bristol • Cardiff • Douglas • Edinburgh • Kendal • Leeds • Liverpool • London • Manchester • Nottingham

Curtins

Woodside Mews, Clayton Wood Close,

Leeds, LS16 6QE

Tel: 0113 274 8509

www.curtins.com

EB1285 South Shields New Central Library & Digital Media Centre


Rev A | Copyright © 2014 Curtins Consulting Ltd Page i

Rev Description Issued by Checked Date

- Phase 2 Ground Investigation Report RGB AB 25/04/2014

A Phase 2 Ground Investigation Report RGB RGB 20/06/2014

This report has been prepared for the sole benefit, use, and information for the client. The liability of Curtins

Limited with respect to the information contained in the report will not extend to any third party.

Author Signature Date

R. Bowman BSc (Hons) MSc CEng MCIWEM C.WEM Senior Environmental Engineer

20/06/2014

Reviewed Signature Date

R. Bowman BSc (Hons) MSc CEng MCIWEM C.WEM Senior Environmental Engineer

20/06/2014

Authorized Signature Date

P.D. Winterburn BSc (Hons) CEng MICE MIStructE Technical Director

20/06/2014



Rev A | Copyright © 2014 Curtins Consulting Ltd Page ii

Executive Summary

Appointment In January 2014 Curtins were instructed by Muse Developments to undertake a Phase 2 Ground Investigation of two parcels of land separated by Ferry Street, South Shields the eastern portion of which had most recently been occupied by Woodhave House. Development Proposals Development proposals comprise the construction of South Shields New Central Library & Digital Media Centre as well as associated car parking and a pedestrian link. The Existing market place will also be remodelled including the erection of a market stall canopy structure. Fieldworks The site investigation fieldworks were undertaken over two stages; the first January 2014 comprised the advancement of; three cable percussion boreholes within the New Central Library & Digital Media Centre building footprint and the second stage in March 2014 comprised the advancement of six machine excavated trial pits as well as machine excavated trial trenches to expose existing foundations. Ground Model The revealed ground model is consistent with the development sites’ former uses with demolition arisings present across both site areas. Laboratory Testing Representative samples of the shallow site soils (made-ground) and underlying natural deposits were obtained and submitted to a suitably accredited laboratory for environmental chemistry analysis. The environmental chemistry results have been compared with the Tier 1 criteria for soils with respect to human health for the intended ‘Commercial’ end use and no exceedances were recorded. Quantitative Risk Assessment – Human Health The risk presented by the made-ground and natural soils to human health is considered to be low and consequently, no remedial action is recommended. Quantitative Risk Assessment – Controlled Waters The risk to the underlying Secondary A aquifer and the nearest surface water feature is considered to be Low considering: the low levels of potential soil contamination encountered within the site made-ground and natural soils and given the lack of nearby potable abstractions and the fact the site is not located within a Source Protection Zone. Quantitative Risk Assessment – Ground Gases The risk from ground gases is considered to be very low and consequently no gas protection measures recommended within the New Central Library & Digital Media Centre. Geotechnical Considerations Geotechnical advice is presented herein with recommendations made for a piled foundation solution. As part of the enabling works a reduced level excavation is recommended to remove the numerous below ground obstructions encountered during the ground investigation. Unexploded Ordnance The likelihood of encountering unexploded ordnance on both development sites is considered to be low either as a result of the proposed works (shallow excavations) or through an assessment based on available evidence. It is recommended that all operatives undertaking intrusive works are informed to the potential (low) presence of unexploded ordnance. The report does not recommend any special measures are adopted. Furthermore, in any event should unexploded ordnance be encountered on site the procedure is: “stop work immediately, prevent access to the area and inform the police”.



Rev A | Copyright © 2014 Curtins Consulting Ltd Page i

Table of contents

Executive Summary ............................................................................................................................................ ii

1.0 Introduction .............................................................................................................................................. 1

1.1 Project background .......................................................................................................................... 1

1.2 Scope of Works ................................................................................................................................ 1

2.0 Phase 1 Desk Study Summary ............................................................................................................... 2

2.1 Current Setting ................................................................................................................................. 2

2.2 Site History ....................................................................................................................................... 2

2.3 Geology ............................................................................................................................................ 2

2.4 Hydrogeology ................................................................................................................................... 3

2.5 Landfills ............................................................................................................................................ 3

2.6 Mining and Radon ............................................................................................................................ 3

2.7 Unexploded Ordnance ..................................................................................................................... 4

2.8 Existing Reports ............................................................................................................................... 5

2.9 Other Significant Factors Potentially Affecting Re-development ..................................................... 5

3.0 Phase 2 Investigation Proposals ............................................................................................................. 6

4.0 Fieldwork ................................................................................................................................................. 7

4.1 General ............................................................................................................................................. 7

4.2 Cable Percussion Borehole Investigation ........................................................................................ 7

4.3 Machine Excavated Trial Pit Investigation ....................................................................................... 8

4.3 Machine Excavated Trial Trenching Investigation ........................................................................... 8

5.0 Laboratory Testing................................................................................................................................... 9

5.1 Environmental Chemistry Testing .................................................................................................... 9

5.2 Geotechnical Testing ..................................................................................................................... 10



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6.0 Ground Conditions................................................................................................................................. 11

6.1 Made-Ground ................................................................................................................................. 12

6.2 Natural Deposits ............................................................................................................................. 12

6.3 Groundwater ................................................................................................................................... 12

7.0 Geochemical Ground and Groundwater Assessment ........................................................................... 13

7.1 Overall Assessment ....................................................................................................................... 13

7.2 Site Soils ........................................................................................................................................ 15

7.3 Controlled Waters........................................................................................................................... 16

7.4 Soil Gases ...................................................................................................................................... 17

8.0 Geotechnical Assessment ..................................................................................................................... 19

8.1 Structural Design Details ................................................................................................................ 19

8.2 Ground Conditions ......................................................................................................................... 19

8.3 Foundation Design ......................................................................................................................... 21

8.4 Ground Floor Slabs ........................................................................................................................ 22

8.5 Settlement and Heave Considerations .......................................................................................... 22

8.6 Excavations .................................................................................................................................... 22

8.7 Concrete Design............................................................................................................................. 23

8.8 Roads and Hardstanding Design ................................................................................................... 23

8.9 Water Supply Pipes ........................................................................................................................ 24

8.10 Soakaways ..................................................................................................................................... 24

9.0 Pre-Remediation Constraints and Outline Remediation Strategy ......................................................... 25

9.1 Invasive Plants ............................................................................................................................... 25

9.2 Services .......................................................................................................................................... 25

9.3 Buildings and Hardstanding ........................................................................................................... 25

9.4 Land Condition and Outline Remediation ...................................................................................... 25

9.5 Recommendations ....................................................................................................................... 266

Appendices ...................................................................................................................................................... 27



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Appendices

Appendix A1 - Site Plans

Appendix A2 - Exploratory Hole Location Plan

Appendix A3 - Exploratory Hole Logs

Appendix A4 - Laboratory Testing Results

Appendix A5 - Tier 1 Thresholds



Rev A | Copyright © 2014 Curtins Consulting Ltd Page 1

1.0 Introduction

1.1 Project background

In January 2014 Curtins were instructed by Muse Developments to undertake a Phase 2 Ground

Investigation of two parcels of land separated by Ferry Street, South Shields one of which had most

recently been occupied by Woodhave House.

Development proposals comprise the construction of South Shields New Central Library & Digital

Media Centre as well as associated car parking and a pedestrian link. The Existing market place will

also be remodelled and a new market stall canopy structure erected.

The site location and development plans for the development can be referred to within Appendix A1.

1.2 Scope of Works

The Phase 2 Ground Investigation was undertaken in order to provide an assessment of the ground

conditions on the subject site with respect to any potential contamination in the underlying soils and or

groundwater.

Specifically the Phase 2 report is intended to determine,

a) If there is a risk of the proposed end user being adversely impacted upon by potential

contamination in shallow site soils that may be present on the site due to its known current,

recent and historical use.

b) If there is a risk of groundwater and/or surface water being adversely impacted upon by

potential contamination that may be present on the site due to its known current, recent and

historical use.

c) If there is a risk to the end user from soil gases including methane, carbon dioxide, oxygen

and hydrogen sulphide.

d) Recommendations for the design of foundations and building ground floor slabs.

e) Recommendations for the specification of sub-structure concrete and water supply pipes.




2.0 Phase 1 Desk Study Summary

This section of the report presents a summary of Curtins Phase 1 Desk Study reporting (ref.

EB1285/NF/R1 dated February 2014)

2.1 Current Setting

The development site is divided into two areas, west and east of Ferry Street approximately 750m

west of South Shields town city centre.

A site location plan is presented in Appendix A1.

2.2 Site History

With reference to the earliest historical maps (mid 1800s) the eastern part of the site was occupied by

two blocks of terraced housing, whilst the western part of the site was occupied with a large glass

works which extended south west of the site. The glass works appears to become disused in the late

1800s and is potentially used as part of the colliery staithes (landing stage), situated adjacent to the

river thereafter.

The former glass works building on the west of the site is demolished in the 1950’s and replaced with

extensive railway sidings and small outbuildings which extend onto the site. The terraced housing on

site is noted as ‘ruins’ in the late 1960’s and soon afterwards, demolished and replaced with large

civic buildings labelled as ‘Woodhave house, Government buildings’ which remains on site until 2013

mapping. From site reconnaissance it is known that these buildings have now been demolished. The

railway sidings and associated buildings on and adjacent to the western side of the site remain

present until the early 1990s, when this part of the site becomes vacant, remaining this way until the

present day.

2.3 Geology

A study of the Envirocheck records and British Geological Survey (BGS) 1:50000 mapping records

(Bedrock and Superficial Editions) for Tynemouth indicates the following geological succession

underlying the site’s as follows;

• Made-Ground deposits (indicated on the western portion of the site only).

• Glaciolacustrine deposits, including clay and silt of Devensian age.

• Pennine Middle Coal measures formation including sandstone, siltstone and mudstone of

Bolsovian (Westphalian C)/Duckmanthian (Westphalian B) age.




2.4 Hydrogeology

The 1:10,000 Groundwater Vulnerability Map indicates that the site, corresponding with the underlying

solid geology, overlies a Secondary A Aquifer. These are;

Permeable layers capable of supporting water supplies at a local rather than

strategic scale, and in some cases forming an important source of base flow to

rivers. These are generally aquifers formerly classified as minor aquifers.

The site superficial deposits are considered to be unproductive.

The site soils are of ‘high leaching potential’ (U); soil information for restored mineral working and

urban areas is based on fewer observations than elsewhere. Therefore a worst case vulnerability

classification (H) is assumed until proven otherwise.

The site is not situated within a Source Protection Zone (SPZ).

The nearest surface water feature is recorded 44m west of site (The River Tyne). No water quality

data is provided for this section of The River Tyne however it is known to be a salmonoid river further

upstream whose quality is improving.

There are no recorded groundwater or surface water abstractions recorded within 1000m of the site.

No discharge consents, local authority pollution prevention and control permits or pollution incidents to

controlled waters are recorded on the site.

The site is not situated in an area that is at risk from extreme flooding or flooding from rivers or sea

without defences.

2.5 Landfills

There are no Environment Agency (EA) or British Geological Society (BGS) recorded landfill sites,

historic or currently operational, on or within 250m of the site.

2.6 Mining and Radon

The Coal Authority Mining Report confirms that the site is in an area which may be affected by mining

activity confirmed within the historical mapping and Envirocheck Report with a large local historic

colliery identified 287m south east of site (St Hildas Colliery), operation is known to have ceased.

The Envirocheck Report indicates two other BGS recorded mineral sites exist within 500m of the site

including Swinburnes Brick field 333m south-east of site and Oystons Brick Fields 362m east of site,

operations at both these mineral sites are known to have ceased.




The Coal Authority Mining Report confirms the site is in the likely zone of influence from workings of 2

seams of coal at 140m to 180m depth last worked in 1916. Any ground movement from these coal

workings should have stopped by now.

There are no known mine entries within 20m of the boundary of the site. The site is not in the likely

zone of influence of any present underground coal workings. The site is not in an area for which the

Coal Authority has determined or is determining whether to grant a licence to, nor is the site in an area

that is likely to be affected by any planned future workings. However coal reserves do exist in the area

which could be worked at some time during the future.

The site is not within the boundary or within 200m of the boundary of an opencast site which coal has

or is being removed by opencast methods. The site is not within 800m of an opencast site of which

the Coal Authority have granted a license for coal removal by opencast methods or within 800m of a

site which the Coal Authority is determining whether to grant a license.

The Coal Authority has not received a damage notice or claim for the subject site or any property

within 50 metres, since 31st October 1994. There is no current Stop Notice delaying the start of

repairs or remedial works to the site. The report also confirms the Authority is not aware of any

request having been made to carry out preventive works before coal is worked under section 33 of the

Coal Mining Subsidence Act 1991.

Both the Radon Atlas for England and Wales and the Envirocheck report presented within the Phase

1 Desk Study confirm that the site is in an area where less than 1% of homes are affected by radon.

No radon protective measures are therefore considered necessary in the construction of new

dwellings or extensions.

2.7 Unexploded Ordnance

South Shields was subject to multiple Luftwaffe bombing raids during the Second World War and

received a high number of high explosive bombs. Indicative risk mapping therefore places the site in

a high risk area.

The Tyneside area was a target due to its industrial activity and owing to South Shields location on the

coast the Luftwaffe may have dropped any remaining ordnance on return from other target locations

along the Tyne. Online testimonials including a letter from the 3rd October 1941 suggest some large

bombing raids were experienced in South Shields where a young teacher describes bombing raids in

which resulted in approximately 30 deaths and 250 houses destroyed. The presence of a ruin on site

in the post-war period is suggestive of direct bomb strikes on the site.




Unexploded Ordnance Risk Assessment reports undertaken by BAE Systems in February 2008 and

April 2014 (Report Ref: A0805-00-R1-3 and A1128-00-R1-1 respectively) relate to both the car park

(2008 report) and the New Central Library & Digital Media Centre (2014 report).

The 2008 report (car park) concludes by determining this portion of the development site as a ‘high’

risk area. The report does however state that the majority of shallow ground is likely to have been

disturbed on site since WWII (considering previous cycles of development), and therefore supervision

of shallow excavations by an explosives safety engineer is unlikely to significantly reduce the risk and

is not recommended, neither are ordnance awareness briefings for personnel involved in shallow

excavations. Considering the end use of this portion of the development site; road and car park

construction including shallow excavations for services this risk is evaluated as low.

The 2014 report (New Central Library & Digital Media Centre) concludes by determining an overall low

likelihood of encountering unexploded ordnance on the site. The report recommends that all

operatives undertaking intrusive works are informed to the potential (low) presence of unexploded

ordnance. The report does not recommend any special measures are adopted.

In any event both reports clarify the procedure should unexploded ordnance be encountered on site:

stop work immediately, prevent access to the area and inform the police.

2.8 Existing Reports

The existing Unexploded Ordnance Risk Assessment reports undertaken by BAE Systems in

February 2008 and April 2014 (Report Ref: A0805-00-R1-3 and A1128-00-R1-1 respectively) were

reviewed within Section 2.7 above.

No other existing reports have been made available for review.

2.9 Other Significant Factors Potentially Affecting Re-development

No other significant features are noted that could potentially affect re-development.




3.0 Phase 2 Investigation Proposals

The Desk Study, as summarised in Section 2.0, revealed an overall ‘Low to Moderate’ level of potential risk

to the end user.

Consequently the Desk Study concluded that there could be a risk of the site end user and controlled waters

being adversely impacted upon by material potentially present on the site.

A strategy for the initial Phase 2 Ground Investigation was derived accordingly and comprised the following

operations,

• Advancement, logging and sampling of representative soils in three cable percussion boreholes with

installations in all boreholes to allow water sampling and gas monitoring to be undertaken.

• Advancement, logging and sampling of representative soils in six machine excavated trial pits.

• Advancement of machine excavated trial trenches to investigate existing pile positions.

• Environmental chemistry analysis for a suite of determinands reflecting the known use of the site on a

number of samples representative of the made-ground and natural materials encountered.

• Geotechnical analysis (both in-situ and laboratory) representative of the ground conditions

encountered.

• Gas and groundwater monitoring within upgraded boreholes.




4.0 Fieldwork

4.1 General

The site investigation fieldworks were undertaken over two stages; the first January 2014 comprised

the advancement of; three cable percussion boreholes within the building footprint and the second

stage in March 2014 comprised the advancement of six machine excavated trial pits as well as

machine excavated trial trenches to expose existing foundations.

Appropriate chemical and geotechnical samples were obtained representative of the ground

conditions revealed.

Curtins drawing ref. EB1285/L001 records the locations of the exploratory holes a copy of which is

contained within Appendix A2.

4.2 Cable Percussion Borehole Investigation

Three cable percussion boreholes were advanced on the subject site under the supervision of a

suitably experienced engineer. The boreholes were logged in general accordance with BS5930: 1999.

The cable percussion boreholes were terminated within the superficial deposits after chiselling for a

minimum of 2 hours.

On advancement water strikes were recorded within all boreholes at the depths detailed in Table 4.2a.

Table 4.2a Cable Percussion Boreholes: Water Strikes

Borehole Reference

Strike (m bgl)

Resting Level after 20mins (m bgl)

Productive Strata

BH1 3.20 3.00 Very clayey, silty, SAND

BH2 15.20 14.00 Possible sand lens

BH3 5.10 14.10

4.50 13.80

Sandy, slightly gravelly CLAY Possible sand lens




A single well standpipe installation was incorporated within each of the three cable percussion

boreholes as detailed in Table 4.2 below.

Table 4.2b Cable Percussion Boreholes: Response Zones

Borehole Reference

Response Zone(s) (m bgl)

Strata Description(s) (Principal strata in capitals)

BH1 2.00 to 4.00 Slightly sandy, slightly gravelly CLAY over very clayey,

silty sand over Slightly sandy, slightly gravelly CLAY

BH2 1.00 to 4.00 MADE-GROUND over slightly sandy, slightly gravelly

clay.

BH3 12.00 to 15.00 Slightly sandy, slightly gravelly CLAY

The response zones were targeted at; a) water bearing strata, b) strata likely to have the highest

permeability and c) strata with the greatest gassing potential.

The response zone targeted the natural soils. Given the composition (no visual or olfactory evidence

of contamination) of the made-ground deposits the effect of creating preferential pathways was

considered to carry an overall low risk to the underlying aquifer.

Copies of all borehole logs can be referred to in Appendix A3 of this report.

4.3 Machine Excavated Trial Pit Investigation

Six machine excavated trial pits were excavated across the full development site; four across the car

park site (TPC1 to TPC4) and two across the New Central Library & Digital Media Centre site (TP14

and TP16). The trial pits were advanced across the subject site under the supervision of a suitably

experienced engineer and were logged in general accordance with BS5930: 1999.

All excavations remained open on completion and on advancement groundwater ingress was not

encountered within any machine excavated trial pit.

Copies of all trial pit logs can be referred to in Appendix A3 of this report.

4.4 Machine Excavated Trial Trenching Investigation

A total of 20 No. machine excavated trial pits/trenches were excavated across the New Central Library

& Digital Media Centre development site. The trial pits/trenches were advanced across the subject

site under the supervision of a suitably experienced engineer and, in accordance with the agreed

scope of works, the locations and dimensions of any piles revealed or below ground features

recorded.




5.0 Laboratory Testing

5.1 Environmental Chemistry Testing

A programme of environmental chemistry testing was scheduled reflecting the findings of the

summary desk study and on-site observations.

The sampling positions (boreholes) were generally located in a non-targeted, systematic array to give

adequate and representative coverage of the site accounting for the historical site use, end use of the

site and the immediate environmental setting.

5.1.1 Soil Analysis

The nature and type of soil contamination potentially present on the site was considered to

include, amongst others; organic matter, ash and fill, hydrocarbons (e.g. fuel oils), heavy

metals and asbestos the extent of which is captured by the broad environmental testing

suite listed in Table 5.1.1 below.

Table 5.1.1 Environmental Chemistry Analysis Suite: Soils

Suite Ref

Analysis LOD Suite

Ref Analysis LOD

S1A

Asbestos Screen

pH Soil Organic Matter

Arsenic

Boron (water soluble) Cadmium Chromium

Chromium VI Copper Lead

Mercury Nickel

Selenium Zinc

Cyanide (total) Sulphate (total)

Sulphide Sulphur (elemental)

Phenols (screen)

PAH’s (USEPA16)

TPH (CWG Banding - Aro/Ali Split)

5 mg/kg 1 mg/kg

0.5 mg/kg 5 mg/kg 5 mg/kg 5 mg/kg 5 mg/kg

0.1 mg/kg 5 mg/kg 5 mg/kg 5 mg/kg

10 mg/kg

200 mg/kg 2 mg/kg

20 mg/kg

1 mg/kg 0.1 mg/kg

0.01 mg/kg

to 0.1 mg/kg

S1B

pH

Soil Organic Matter

Arsenic Boron (water

soluble) Cadmium Chromium

Chromium VI Copper Lead

Mercury Nickel

Selenium Zinc

Cyanide (total) Sulphate (total)

Sulphide Sulphur (elemental)

Phenols (screen)

PAH’s (USEPA16)

TPH (Total)

5 mg/kg 1 mg/kg

0.5 mg/kg 5 mg/kg 5 mg/kg 5 mg/kg 5 mg/kg

0.1 mg/kg 5 mg/kg 5 mg/kg 5 mg/kg

10 mg/kg 200 mg/kg 2 mg/kg 20 mg/kg

1 mg/kg

0.1 mg/kg

0.01 mg/kg to 0.01 mg/kg




Soil samples were taken from the shallow made-ground deposits in each of the three cable

percussion borehole locations as well as the machine excavated trial pits (TPC1 to TPC4)

and tested for Suite S1a. Soil samples were also taken from the deeper natural soils (BH1

and BH3) or made-ground soils (BH2) and tested for Suite S1b.

Copies of the environmental chemistry testing certificates can be referred to in Appendix A4

of this report.

5.1.2 Groundwater Analysis

Minimal groundwater ingress was encountered on advancement of boreholes and therefore

groundwater sampling was not undertaken during the fieldwork.

Groundwater sampling and analysis was not scheduled on return monitoring following receipt

and appraisal of the soil analysis results detailed herein.

5.2 Geotechnical Testing

A programme of geotechnical testing was scheduled in order to develop the ground model for the site.

Geotechnical samples representative of the main soil types encountered on site were tested for the

suites detailed in Table 5.2 below.

Table 5.2 Geotechnical Analysis Suite

Suite Reference Geotechnical Analysis

G1a Natural moisture content (BS 1377-2: 1990 Clause 3.2)

G1b Atterberg limits (BS 1377-2: 1990 Clauses 4.3 and 5)

G1c Particle size distribution (BS 1377-2: 1990 Clause 9.2)

G1d Water soluble sulphate & pH (BS 1377-3: 1990 Clauses 3, 5.2, 5.5, 7.2 & 9)

G1e Multistage undrained triaxial (BS 1377-7: 1990 Clause 9) with cell pressure of overburden x 0.5, 1 and 2




6.0 Ground Conditions

The revealed site geology was consistent with the anticipated geology and historical use of the site with the

generalised geological succession is summarised in Table 6.0 below.

Table 6.0 Summary of Generalised Geological Succession

Strata Depth Range (m bgl) Description

MADE GROUND 0.00 to 3.70

Across the New Central Library & Digital Media Centre site:

Predominantly granular (gravels) with cohesive (clay) inclusions or full lenses, typically at shallower depths.

Silty, sandy, cobbly occasionally bouldery (brick fill or

demolition arisings)

Local and occasional obstructions, e.g. relic brick walls or concrete slabs.

Across the car park site:

As above but without obstructions and including a band

(0.40m to 0.70m thick) of suspected ballast (brown to dark brown, ashy, silty, sandy gravel of flint, quartzite, sandstone

and brick)

CLAY 1.10 to 18.50

Across the New Central Library & Digital Media Centre site:

Firm to very stiff becoming stiff or hard respectively, sandy, gravelly, cobbly occasionally bouldery. Infrequent sand

lenses.

Soft to firm (BH3 only; 5.00m to 5.50m).

Silt band (BH1 only; 7.10m to 8.50m)

SAND 3.00 to 4.00

Across the car park site:

Silty, gravelly, sand with occasional shell fragments (TPC1) and hydrorcarbon odour (TPC2). Possible made-ground.




6.1 Made-Ground

Made-ground deposits were encountered in all exploratory hole locations to a maximum depth of

3.70m bgl. The made-ground deposits are broadly consistent with demolition arisings, predominantly

granular silty, sandy, gravelly, cobbly brick fill and with local and occasional obstructions, e.g. relic

brick walls and concrete slabs. Where present, gravel comprises; angular brick, concrete and

sandstone.

As part of the machine excavated trial trench investigation as well as relic brick wall and concrete

slabs, relic pile caps and relic piles were revealed across the development site associated with the

former Woodhave House building.

The co-ordinates of all revealed piles and buried obstructions encountered as part of the trial

trenching investigation are presented in Appendix A2.

Within the car park site a limited (0.40m to 0.70m) band of suspected ballast was encountered at the

base of the made-ground deposits.

With the exception of grey mottling and a hydrocarbon odour within the made-ground soils of TPC2,

within the car park site, no olfactory or visual evidence of free product contamination was noted within

the made-ground deposits.

6.2 Natural Deposits

Superficial deposits were encountered beneath the made-ground deposits, in the majority of

exploratory hole locations excluding TPC3 and TPC4 within the car park site.

The superficial deposits were predominantly cohesive in nature, generally consistent across the

development site and comprised; initially firm to very stiff, becoming stiff to hard brown to dark grey

sandy gravelly clay with infrequent sand lenses

Bedrock deposits were not encountered within any exploratory hole locations

No visual evidence of contamination, e.g. staining, was noted within the natural soils.

Olfactory evidence of contamination (hydrocarbon odour) was noted within the sand deposits of

TPC2.

6.3 Groundwater

On advancement of the cable percussion boreholes groundwater strikes were recorded as detailed in

Table 4.2a within Section 4.2. On return monitoring visits groundwater levels were recorded between

2.89m (BH1) and 8.13 (BH3).

No groundwater ingress was recorded on advancement of the machine excavated trial pits.




7.0 Geochemical Ground and Groundwater Assessment

7.1 Overall Assessment

The Summary Phase 1 Desk Top Study presented in Section 2.0 revealed an overall, ‘Moderate to

Low’ level of potential risk to the end user.

A strategy for a Phase 2 Ground Investigation was consequently developed with reference to this

information, the initial conceptual site model and the development use as ‘Commercial’.

The ground investigation was undertaken in order to provide an assessment of the ground conditions

on the subject site with respect to potential contamination in the underlying soils and the risk from soil

gases.

This section of the report includes the assessment of the potential contamination, solid, liquid and

gas, identified on the subject site which may present a risk to the end users, associated utilities and

the wider environment.

Curtins use a tiered approach in assessing the risk from potential contamination, such assessment

being based on the known history of the site as determined by the desk study in conjunction with

observations made during the ground investigation. This assessment is based solely on the results of

the chemical and other testing data obtained as part of Curtins Consulting’s investigation.

Under the Contaminated Land (England) Regulations 2000 a Local Authority has from time to time to

survey the land within its boundaries to identify “Contaminated Land”. This is land “in such condition,

by reason of substances in, on, or under the land, that: significant harm is being caused, or pollution

of controlled waters is being or likely to be caused”.

In guidance published by the Environment Agency, the risk to end users or controlled waters is

determined through an assessment of pollutant linkages between a source of contamination and a

sensitive receptor such as house occupants, plants grown in gardens or groundwater abstracted for

drinking. This is termed a source-pathway-receptor relationship.

With respect to this investigation the source is taken as being a point or area of contamination within

the ground. The pathway is a mechanism by which the contamination could reach the receptor.

For instance this could be through eating contaminated soil or plants contaminated through taking up

contamination in the soil through their roots, inhaling contaminated dust or drinking contaminated

water. Other pathways include directly causing degradation of buried building materials such as

plastic or concrete. Further indirect pathways include groundwater transporting contamination to a

groundwater abstraction point or to a river or stream and thus causing it to become polluted.

In order to assess whether a potential pollutant linkage is significant with respect to human health, the

Environment Agency and the Department of the Environment, Food and Rural Affairs (DEFRA),




published in 2002 guidance referred to as the Contaminated Land Exposure Assessment Model

(CLEA). The software originally developed with this model was withdrawn in October 2006 and

subsequently reissued in January 2009 (CLEA v1.04).

A model for assessing the potential for pollution of controlled waters and for deriving a safe

concentration in ground and groundwater is the Environment Agency’s publication “Remedial Targets

Methodology - Hydrogeological Risk Assessment for Land Contamination’.

These models have a common approach, which is one of a tiered assessment. At each stage of the

assessment further detail can be applied to the model to provide a detailed interpretation on a site by

site basis. This is to determine whether the criteria are being met to prevent contamination of

controlled waters and to protect human health and the environment.

This assessment is the first tier in the process. It is a comparison between various sets of generic

criteria and the result of testing from the investigation. Where available these criteria are drawn from

the CLEA guidance itself in the form of Soil Guideline Values (SGV’s).

These values have been derived from lengthy research applying knowledge of the toxicity and

carcinogenicity of substances and the mechanism by which each acts in the environment.

To date there are SGV’s published for only eleven determinands and consequently Curtins Consulting

utilise Generic Assessment Criteria (GAC’s) to supplement these for the Tier 1 assessment as shown

in Appendix A6 of this report.

Currently, within the UK, there are no Tier 1 assessment values published by regulatory bodies for a

wide range of organic compounds, petroleum hydrocarbons, volatile and semi-volatile compounds.

Therefore other guidance maybe referred to, for example the TPH Criteria Working Group series of

documents, the LQM/CIEH and EIC/AGS/CL:AIRE published thresholds.

In relation to the standards for controlled waters, there are currently no generic groundwater

standards or surface water standards that are necessarily applicable to all sites.

However, dependant on the receptor identified as being at risk, the Surface Water (Abstraction for

Drinking Water) and or the Environment Agency’s national Environmental Quality Standards (EQS’s)

are considered appropriate (and are considered acceptable to the Regulators) and are used in this

Tier 1 assessment.

In addition, and in particular where the groundwater or surface water could not be found or sampled in

sufficient quantity, a soil leaching test (BS EN 12457:2002) can be undertaken to provide a

preliminary assessment of the potential for contaminants in the soil to pollute ground or surface water.

The results are compared, again dependant on the receptor identified as being at risk, against the EA

EQS’s and or UK Drinking Water Standards.




Once contaminants of concern have been identified by the Tier 1 assessment, qualitative and or

quantitative risk assessments maybe undertaken to determine whether a viable source-pathway-

receptor linkage is present.

The main end use (New Central Library & Digital Media Centre) of the site is directly accounted for by

published UK guidance; the end uses currently being defined as a) residential with home-grown

produce b) allotments and c) commercial.

7.2 Site Soils

As discussed previously, three cable percussion boreholes and six machine excavated trail pits were

advanced across the development site. Soil samples were taken from the shallow made-ground

deposits in each of the three cable percussion borehole locations as well as the machine excavated

trial pits (TPC1 to TPC4, TP12 and TP14) and tested for Suite S1a. Soil samples were also taken

from the deeper natural soils (BH1 and BH3) or made-ground soils (BH2) and tested for Suite S1b.

As discussed within the previous section, the environmental chemistry results have been compared

with the Tier 1 criteria for soils with respect to human health for the intended ‘Commercial’ end use.

The results of the environmental testing can be referred to in Appendix A4. Copies of the Tier 1

thresholds are contained within Appendix A5.

In the absence of direct readings soil organic matter (SOM) has been conservatively estimated as

1.0%.

With respect to the end use of the site Tier 1 thresholds have not been exceeded within either; the

shallow made ground site soils, the deeper made-ground soils or the underlying natural soils (BH1

and BH3). Consequently, the risk presented by the made-ground soils to human health is considered

to be low.

It is recommended that construction workers are to be provided with appropriate PPE and sanitary

facilities with reference to the contaminants of concern observed in the site soils.

7.2.1 Waste Classification

An preliminary assessment for the waste classification of the site soils encountered on site

has been conducted both through an appraisal of the environmental chemistry results and

using the Waste Soils Characterisation Assessment Tool, Cat-WasteSoil, developed by

McArdle and Atkins. The first stage of assessment comprises a comparison of the soil

analysis results against Tier 1 thresholds for ‘Residential without Homegrown Produce’ to

determine the likelihood of soils being inert or greater. Subsequently and where necessary,

the Cat-WasteSoil tool gives a rapid assessment of contaminated soils and their classification

as either hazardous or non-hazardous waste.




The preliminary classification of the main materials is presented in Table 7.2.1 below.

Table 7.2.1 Waste Classification of Materials

Stratum

Preliminary Classification

Stage 1: Based on appraisal of soil

analysis results

Stage 2: Based on Cat-WasteSoil

assessment

Made-ground Inert (3) 1 N/A

Natural Drift Inert (2) 1 N/A

Note 1: Brackets denote dataset size.

Further WAC environmental analysis of the shallow soils encountered during the

redevelopment of the site will need to be carried out to confirm the above classifications if

the material is to be taken off site.

It should be noted that the preliminary waste classification is undertaken to offer indicative

advice with respect to disposal requirements. Landfill operators are not obliged to accept

waste and, if they were to do so, may have specific requirements beyond those outlined

above prior to acceptance.

7.3 Controlled Waters

On advancement of the cable percussion boreholes groundwater strikes were recorded as detailed in

Table 4.2a within Section 4.2.

On return monitoring visits groundwater levels were recorded between 2.89m (BH1) and 8.13 (BH3).

No groundwater ingress was recorded on advancement of the machine excavated trial pits.

Groundwater sampling was not scheduled given the low levels of potential contamination determined

within the site soils (made-ground and natural) and the lack of evidence of contamination within the

waters. It is therefore considered that the risk to the underlying Secondary A aquifer and the nearest

surface water feature (the River Tyne, 44m west of site) is Low for these reasons and given the lack of

nearby potable abstractions and the fact the site is not located within a Source Protection Zone.




7.4 Soil Gases

7.4.1 Asphyxiant, Noxious or Explosive Gases

Standpipe installations were incorporated in all three cable percussion borehole locations as

detailed in Table 4.2 in Section 4.

An initial programme of six gas monitoring visits over three months was proposed. To date,

all six gas monitoring visits has been completed on the following dates: 17 February 2014,

06 March 2014, 14 March 2014, 02 April 2014, 07 April 2014 and 16 April 2014.

A summary of the soil gas monitoring results to date is presented in Tables 7.4.1 below and

copies of the log sheets presented in Appendix A5.

Table 7.4.1 Summary of Soil Gas Monitoring Results

Borehole Reference

CO2 Range (% vol/vol) Max GSV

(l/hr) CH4 Range (% vol/vol)

Max GSV (l/hr)

BH1 0.0 to 0.2 0.0002 < 0.1 <0.0001

BH2 < 0.1 <0.0001 < 0.1 <0.0001

BH3 0.0 to 0.2 0.0002 < 0.1 <0.0001

A maximum concentration of carbon dioxide of 0.2% vol/vol was determined whilst a maximum

concentration of methane less than 0.1% vol/vol. was determined.

No hydrogen sulphide or carbon monoxide was detected.

A maximum absolute soil gas flow rate of less than 0.1l/hr was determined.

Barometric pressure was recorded between 1002mb and 1020mb across the monitoring

visits with four falling pressure events.

Considering potential on-site gas generating sources: The gas generation potential of

the made-ground soils is considered to be low based on the stratum description but

accounting for its nature (demolition fill) that may contain limited amounts of timber.

Considering potential off-site gas generating sources: The Desk Study revealed no

Environment Agency (EA) or British Geological Society (BGS) recorded landfill sites, historic

or currently operational, within 250m of the site. Alluvial deposits and made-ground soils

surrounding the site are therefore identified as the main, off-site potential sources the gas

generation potential of which, in the absence of specific data, is considered to be moderate

to low.




Considering the ground model (potential pathways): Demolition fill is recorded across

the entire development site underlain by cohesive soils. Consequently, the pathways along

which gases may potentially migrate are considered to be short and direct (direct gassing of

made-ground soils into sub-floor space).

Considering the end use of the site (potential receptors): The commercial end use is of

a low sensitivity with potentially long exposure durations albeit within predominantly large

internal air spaces.

Considering both a ‘worst credible scenario’ (maximum ‘absolute’ flow rate, maximum gas

concentration within a single borehole location) and ‘worst possible scenario’ (maximum

‘absolute’ flow rate, maximum gas concentration across all borehole locations) the Gas

Screening Values (GSV) for the site are evaluated as 0.0002 (carbon dioxide) and <0.0001

(methane).

Considering the gas monitoring results to date gas protection measures are not considered

necessary within the development.

7.4.2 Radon

Both the Radon Atlas for England and Wales and the Envirocheck report (presented as part

of the Phase 1 Desk Study) confirm that the site is in an area where less than 1% of homes

are affected by radon. No radon protective measures are therefore considered necessary in

the construction of new dwellings or extensions.




8.0 Geotechnical Assessment

8.1 Structural Design Details

Development proposals comprise the construction of South Shields New Central Library & Digital

Media Centre as well as associated car parking and a pedestrian link. The Existing market place will

also be remodelled and a new market stall canopy structure erected. For the Central Library & Digital

Media Centre unfactored loads of 4000kN and 2500kN have been estimated for the perimeter and

internal columns respectively.

A copy of the development plan for the site can be referred to within Appendix A1.

8.2 Ground Conditions

Made-ground deposits consistent with recent demolition arisings were encountered across the

development site to comparable depths (max. 3.70m bgl). Across the car park site similar made-

ground deposits were encountered albeit underlain by older, suspected ballast consistent with the

site’s history; glass works and the fringes of railway sidings.

The calorific value of the made-ground soils was tested in one location (BH1) where burnt shale, coal

and clinker were encountered and confirmed to be <1.0MJ/kg.

No evidence of the made-ground soils having been re-engineered (specific compaction regime) was

noted and occasional, local obstructions were noted consistent with both historical uses of the site

(relic, brick basement walls) and more recent use of the site (relic pile caps and concrete slabs).

Underlying the made-ground soils drift deposits (predominantly cohesive) were encountered to a

maximum depth of 18.50. Plasticity testing on the natural clay deposits indicates that they are of low

plasticity and predominantly fine grained with >90% of the sample mass passing 450µm in the

majority of samples.

No bedrock deposits were encountered.

Results of the in-situ standard penetration testing (SPT) broadly confirmed the field observation with

‘N’ values generally increasing down the soil profile as illustrated on the SPT Results Presentation

sheet presented in Appendix A2 and within Table 8.2.

The predominantly cohesive nature of the shallow site soils lends itself of an estimation of undrained

shear strength (cu) and compressibility (mv) from SPT under Stroud’s (1974) and Stroud and Butler’s

(1975) empirical relationships. The empirical workings are informed by an understanding of the soils

plasticity, site history and local geology. Plasticity testing results confirm a low volume change

potential.




Consequently, based on average, uncorrected N values the undrained shear strengths (cu) and

coefficients of volume compressibility (mv) can be estimated as detailed in Table 8.2.

Table 8.2 Estimated Geotechnical Parameters (based on Stroud, 1974 and Stroud & Butler, 1975)

Depth (m) Mean ‘N’ values ±

standard error cu mv

1.00 19 ± 9 Granular made-ground Granular made-ground

3.00 42 ± 4 252 kN/m2 25200 m2/MN

5.00 41 ± 5 246 kN/m2 24600 m2/MN

7.00 45 ± 5 270 kN/m2 27000 m2/MN

9.00 35 ± 3 210 kN/m2 21000 m2/MN

11.00 38 ± 6 228 kN/m2 22800 m2/MN

13.00 50 ± 0 300 kN/m2 30000 m2/MN

15.00 50 ± 0 300 kN/m2 30000 m2/MN

17.00 50 ± 1 300 kN/m2 30000 m2/MN

18.00 50 300 kN/m2 30000 m2/MN

The estimated undrained shear strengths correspond with ‘stiff’ to ‘very stiff’ cohesive soils.

It should be noted that these values are based on averaged N values without consideration of the

effects of overburden.

The estimations of undrained shear strength were broadly consistent with the shear stresses

determined through the multi-staged triaxial testing undertaken within the clay soils the results of

which are presented within Appendix A4 together with all other laboratory testing certificates.

Two U100 samples (BH1 at 6.00m and BH2 at 14.00m) failed prior to sampling due to the presence of

silt laminations and cobbles.




8.3 Foundation Design

On the basis of observations made on site together with results of in-situ and laboratory test it is

considered that the natural clay deposits would be considered favourable for founding upon however,

given the anticipated loadings and the depths to which spread foundations would need to be extended

a piled foundation solution will likely provide a more economic foundation solution for the New Central

Library & Digital Media Centre.

8.3.1 Piled Foundations

Pile Type: In light of the ground conditions revealed either a driven or bored piled solution

is considered technically feasible within the development.

Potential Constraints: The proximity of nearby structures may preclude the use of a

driven system owing to undue vibration and noise. Additionally, as part of the enabling

works consideration should be given to the presence of below ground obstructions

including; relic piles, relic brick structures and relic concrete slabs. Investigations into the

presence of relic piles were undertaken as part of the fieldworks operations with around 30

piles located, of a total in the region of 100. During this investigation the presence of

additional, potential obstructions was identified. Consequently, where feasible, these below

ground obstructions should be pre-dug and removed from site or else, for the existing piles,

located and recorded to facilitate the installation of the proposed piles and avoid clashes

respectively.

Temporary Casing: Owing to the presence of perched groundwater lenses within the

natural clay deposits it is recommended that bored piles are cased throughout.

Alternatively, the adoption of Continuous Flight Auger (CFA) or Continuous Helical

Displacement (CHD) piles would likely negate the need for casing.

Chiselling: Very stiff to hard clay deposits were determined within all cable percussion

borehole locations and therefore allowance should be made for chiselling these deposits to

achieve design depths.

Design Criteria: Reference should be made to Table 8.2 and the appended geotechnical

testing results to finalise design criteria. It should be noted that the design procedure for

piles varies across the pile types within an ever evolving discipline. It is therefore

recommended that the advice of a specialist contractor is sought to confirm design criteria.

Environmental Risk Assessment: Given the low levels of potential contamination

determined within the site shallow soils and the termination of the piles within the clay

deposits the risk associated with preferential pathways being created through the use of a

piled foundation solution.




8.4 Ground Floor Slabs

In their current condition the sub-grade (made-ground) is not considered suitable for founding upon

due to the potential for undue total and differential settlement. Consideration should therefore be

given to the adoption of suspended ground floor slabs. Alternatively, consideration could be given to

improving the ground as part of the enabling works, e.g. site turnover and re-compaction of either site-

won or imported granular material achieving an agreed grading specification.

8.5 Settlement and Heave Considerations

Considering the predominantly granular nature of the made-ground soils ground heave will not be a

significant issue and therefore there doesn’t appear to be a requirement to incorporate heave

protection measures in the design of pile/beam foundations.

Furthermore, the plasticity of the natural clay deposits has been shown to be either at or less than

20% and therefore the potential for heave will be limited and pile design undertaken accordingly.

8.6 Excavations

General advice on excavation support is given in CIRIA Report No 97: Trenching Practice. On the

basis of observations on site, together with the results of in-situ and laboratory tests, it is considered

that some excavations are unlikely to stand unsupported in the short term.

Side support for safety purposes should be provided to all excavations which appear unstable, and

those in excess of 1.20m deep, in accordance with Health and Safety Regulations. Excavations

below 1.20m requiring personnel access will require closed side support.

Groundwater should not be expected in excavations for foundations or services and if and where

encountered pumping is considered to be a suitable control measure. The presence of water bearing

granular lenses was noted within 3.00m depth of the site surface and where revealed, pumping

should be avoided to reduce loosening of the surrounding soils. Whilst unlikely, the use of well-

pointing may need to be considered as an alterative de-watering strategy.

General advice on de-watering is given in CIRIA Report No C515: Groundwater Control.




8.7 Concrete Design

In accordance with BRE Special Digest 1 the site has been classified as brownfield land that is

unlikely to contain pyrite and laboratory testing undertaken accordingly on both the made-ground and

underlying natural strata.

The results of chemical tests in the made-ground soils indicate an average sulphate concentration in

the soil of 243mg/l as a 2:1 water/soil extract with pH values in the range of 8.2 to 12.0.

The results of chemical tests in the natural clay soils indicate an average sulphate concentration in the

soil of 172mg/l as a 2:1 water/soil extract with pH values in the range of 8.4 to 9.0.

On the basis of site observations it is considered groundwater be considered nominally mobile and

consequently, based on the laboratory results presented above a Design Sulphate Class for the site

shallow soils may be taken as DS-1 with an Aggressive Chemical Environment for Concrete (ACEC)

class for the site of AC-1.

It is recommended that no significantly disturbed clay is placed against foundations.

8.8 Roads and Hardstanding Design

On the basis of site observations California Bearing Ratio (CBR) testing was not conducted across the

New Central Library & Digital Media Centre site owing to the presence of boulders and the high

cobble content likely to have skewed the results.

Across the adjacent car park site CBR testing was conducted in 4 no. locations (TPC1 to TPC2) at

depths of between 0.50m and 0.60m below ground level and values recorded in the range of 19% to

>37%. Owing to the presence of cobbles and to a lesser extent, boulders within the made-ground

soils it is recommended that a value of no greater than 10% is adopted for preliminary design

purposes.

Generally, any areas of soft or deleterious material in the site shallow soils should be excavated and

replaced with a properly compacted granular fill.

Furthermore, it is recommended that the sub-grade (made-ground) be regarded as frost susceptible

and therefore, in their current condition, a minimum of 450mm sub-base required within the pavement

construction.




8.9 Water Supply Pipes

With reference to the UKWIR publication ‘Guidance for the Selection of Water Supply Pipes to be

used in Brownfield Sites’ document reference 10/WM/03/21 advice is given on the appropriate

materials for these ground conditions.

The low levels of potential contamination do not indicate the presence of adverse toxic, corrosive or

organic conditions within the made-ground soils on site.

It is therefore recommended that all construction materials may be adopted for water supply pipes.

The exact requirements are to be confirmed with the relevant utility supplier.

8.10 Soakaways

Infiltration testing was not conducted as part of the ground investigation. Notwithstanding, the

provision of soakaways is not considered viable given the presence of cohesive natural soils that are

anticipated to have poor infiltration potential. Furthermore, the sand lens identified within BH1 is

considered to be an isolated pocket and therefore suitable as a drainage site.




9.0 Pre-Remediation Constraints and Outline Remediation Strategy

This section of the report describes general constraints to development currently thought to exist on the site of

interest.

9.1 Invasive Plants

The presence of the invasive plants, Japanese Knotweed and or Giant Hogweed, was not apparent during the fieldwork.

9.2 Services

Public Utility information has been obtained for the site.

9.3 Buildings and Hardstanding

The two development sites are currently clear with a former access point (hardstanding surface) and

communications box present on the New Central Library & Digital Media Centre.

9.4 Land Condition and Outline Remediation

The revealed ground model is consistent with the development sites’ former uses with demolition

arisings present across both site areas.

The environmental chemistry results have been compared with the Tier 1 criteria for soils with respect

to human health for the intended ‘Commercial’ end use no exceedances recorded. Consequently,

remedial action is not recommended.

The risk to the underlying Secondary A aquifer and the nearest surface water feature is considered to

be Low considering: the low levels of potential soil contamination encountered within the site made-

ground and natural soils and given the lack of nearby potable abstractions and the fact the site is not

located within a Source Protection Zone.

The risk from ground gases is considered to be very low and consequently no gas protection

measures recommended within the New Central Library & Digital Media Centre development.

The Radon Atlas for England and Wales confirms that radon protection measures are not required

within the development.




9.5 Recommendations

The Phase 2 Ground Investigation has revealed overall lower risks to; end users of the site, controlled

waters, construction materials and construction workers than those indicated by the Phase 1 Desk

Study.

Remedial Action(s): The findings of the ground investigation indicate that no specific remedial

action is recommended to mitigate against risk presented to end users or controlled waters.

Gas Protection Measures: The findings of the proposed six gas monitoring visits indicate that gas

protection measures are not recommended within the New Central Library & Digital Media Centre

development.

Geotechnical Considerations: Geotechnical advice is presented herein with recommendations

made for a piled foundation solution. As part of the enabling works a reduced level excavation is

recommended to remove the numerous below ground obstructions encountered during the ground

investigation.

Unexploded Ordnance: The likelihood of encountering unexploded ordnance on both development

sites is considered to be low either as a result of the proposed works (shallow excavations) or through

an assessment based on available evidence. It is recommended that all operatives undertaking

intrusive works are informed to the potential (low) presence of unexploded ordnance. The report does

not recommend any special measures are adopted. Furthermore, in any event should unexploded

ordnance be encountered on site the procedure is: “stop work immediately, prevent access to the

area and inform the police”.

PPE and Sanitary Facilities: It is recommended that construction workers are to be provided with

appropriate PPE and sanitary facilities with reference to the contaminants of concern observed in the

site soils.

Follow-on Reporting: Whilst no specific remedial actions are recommended is recommended that a

Developers Method Statement is produced to provide advice with respect to earthworks activities,

imported soil specifications and, where necessary, materials management. Additionally, as detailed

herein, consideration may be given to the production of an earthworks specification in support of the

enabling works.

Documents

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